The Celtics took control in the third, outscoring Detroit 34-20 to gain a 91-72 lead.

Boston opened up an 11-point lead early in the third with an 8-0 spurt that included 3-pointers from Hayward and Smart.

When Tatum made a trey from the right side with 6:47 left in the quarter, Boston’s lead was 72-58.

Later in the quarter, Smart drained back-to-back 3-pointers to extend the Celtics’ advantage to 17 at 85-68.

Tatum fired in another long shot in the final minute of the quarter to make it 89-69. Smart made the last basket of the quarter, scoring along the right baseline while falling down.

The Pistons didn’t go quietly. They reeled off a 20-2 run, capped by a Drummond steal and dunk, to cut Boston’s lead to 10. Horford made a 3 to end that outburst. Detroit couldn’t get the deficit into single digits until the final two minutes.